Function updateHostComponent

code/new-context-api/public/app.js:9377–9434

(current, workInProgress, renderExpirationTime)

  }

  function updateHostComponent(current, workInProgress, renderExpirationTime) {
    pushHostContext(workInProgress);

    if (current === null) {
      tryToClaimNextHydratableInstance(workInProgress);
    }

    var type = workInProgress.type;
    var memoizedProps = workInProgress.memoizedProps;
    var nextProps = workInProgress.pendingProps;
    var prevProps = current !== null ? current.memoizedProps : null;

    if (hasLegacyContextChanged()) {
      // Normally we can bail out on props equality but if context has changed
      // we don't do the bailout and we have to reuse existing props instead.
    } else if (memoizedProps === nextProps) {
      var isHidden = workInProgress.mode & AsyncMode && shouldDeprioritizeSubtree(type, nextProps);
      if (isHidden) {
        // Before bailing out, make sure we've deprioritized a hidden component.
        workInProgress.expirationTime = Never;
      }
      if (!isHidden || renderExpirationTime !== Never) {
        return bailoutOnAlreadyFinishedWork(current, workInProgress);
      }
      // If we're rendering a hidden node at hidden priority, don't bailout. The
      // parent is complete, but the children may not be.
    }

    var nextChildren = nextProps.children;
    var isDirectTextChild = shouldSetTextContent(type, nextProps);

    if (isDirectTextChild) {
      // We special case a direct text child of a host node. This is a common
      // case. We won't handle it as a reified child. We will instead handle
      // this in the host environment that also have access to this prop. That
      // avoids allocating another HostText fiber and traversing it.
      nextChildren = null;
    } else if (prevProps && shouldSetTextContent(type, prevProps)) {
      // If we're switching from a direct text child to a normal child, or to
      // empty, we need to schedule the text content to be reset.
      workInProgress.effectTag |= ContentReset;
    }

    markRef(current, workInProgress);

    // Check the host config to see if the children are offscreen/hidden.
    if (renderExpirationTime !== Never && workInProgress.mode & AsyncMode && shouldDeprioritizeSubtree(type, nextProps)) {
      // Down-prioritize the children.
      workInProgress.expirationTime = Never;
      // Bailout and come back to this fiber later.
      workInProgress.memoizedProps = nextProps;
      return null;
    }

    reconcileChildren(current, workInProgress, nextChildren);
    memoizeProps(workInProgress, nextProps);
    return workInProgress.child;
  }